A tilt position adjustment mechanism is a mechanism for adjusting a tilt angle of a steering wheel in a position where a driver can most acquire drive ability in accordance with the physique and preference of the driver. When the tilt angle of the steering wheel is adjusted, a tilt clamping mechanism is once unclamped and after the tilt angle of the steering wheel is continuously adjusted in that state, the tilt angle of the steering wheel is clamped again.
In a steering device provided with such a tilt position adjustment mechanism, a bracket for installing on a vehicle body is fixed to the vehicle body and a clamping rod is inserted into a long groove for tilt adjustment of the bracket for installing on the vehicle body and a column. In clamping a tilt, the tilt is clamped by axially pressing a fixed cam with a movable cam turned by the operation of an operating lever, clamping the clamping rod and pressing the column on the bracket for installing on the vehicle body. However, when the clamping force of the clamping rod is weak, the column is moved in a tilted direction in secondary collision in which a driver violently collides with the steering wheel and it is feared that an air bag provided to the steering wheel cannot receive occupants in an effective position.
For a mechanism for blocking the movement of the column in such secondary collision, a tilt clamping mechanism where a fixed tilt lock gear is provided to a side plate of a bracket for installing on a vehicle body and a clamping rod is inserted into a movable tilt lock gear engaged with the fixed tilt lock gear is proposed.
Owing to this configuration, in clamping a tilt, the clamping rod is clamped by the operation of an operating lever, holding power in a tilted direction is enhanced by engaging the movable tilt lock gear with the fixed tilt lock gear, and even if an impact load by the secondary collision acts on a steering wheel, a column is prevented from being moved in the tilted direction.
In such a steering device in which the holding power in the tilted direction is enhanced, when the operation of the operating lever in clamping the tilt is insufficient, the engagement of the movable tilt lock gear and the fixed tilt lock gear is insufficient and when the impact load by the secondary collision acts on the steering wheel, the column may be moved in the tilted direction.
In a steering device provided with a tilt clamping mechanism disclosed in International Publication No. WO2008/056711, a wire spring configured by another part is attached to a fixed tilt lock gear or an operating lever, the wire spring is fitted to the mated part via respective convex and concave portions and gives click stop feeling, and operation feeling that a movable tilt lock gear and the fixed tilt lock gear are securely engaged is acquired.
However, in the steering device provided with the tilt clamping mechanism disclosed in International Publication No. WO2008/056711, as the wire spring is configured by another part, the number of parts and a man-hour for assembly increase and the manufacturing cost is increased. Besides, when the operation of the operating lever in unclamping the tilt is insufficient, the movable tilt lock gear and the fixed tilt lock gear are engaged halfway and gear noise may be made in tilt adjustment.
International Publication No. WO2008/056711